/*
Mikhail Breslav and Chris Kwan
{breslav, ckwan}@cs.bu.edu
http://cs-people.bu.edu/ckwan/cs511/

CS 511 Spring 2011 Project
Client-side Parsing and Verification

 Function to store propositional atoms in a table.
*/


function getTruthValue(input,table)
{
	
	//for each propositional atom we want to 
	// 1.) check if atom is in the table
	// 2.) if yes, return its truth value
	// 3.) if no, add the atom to the table, give it a truth value, return its truth value
	
	//var table = new hash_atoms();
	var inTable = table.hasItem(input); 
	
	if(inTable)
	{
		return table.getItem(input);
	}
	else
	{
		table.setItem(input,true);
		return table.getItem(input);
	}
	
	    
}

//http://www.mojavelinux.com/articles/javascript_hashes.html
function hash_atoms()
{
	this.length = 0;
	this.items = new Array();
	for (var i = 0; i < arguments.length; i += 2) {
		if (typeof(arguments[i + 1]) != 'undefined') {
			this.items[arguments[i]] = arguments[i + 1];
			this.length++;
		}
	}
	
	this.removeItem = function(in_key)
	{
		var tmp_previous;
		if (typeof(this.items[in_key]) != 'undefined') {
			this.length--;
			var tmp_previous = this.items[in_key];
			delete this.items[in_key];
		}
	   
		return tmp_previous;
	}

	this.getItem = function(in_key) {
		return this.items[in_key];
	}

	this.setItem = function(in_key, in_value)
	{
		var tmp_previous;
		if (typeof(in_value) != 'undefined') {
			if (typeof(this.items[in_key]) == 'undefined') {
				this.length++;
			}
			else {
				tmp_previous = this.items[in_key];
			}

			this.items[in_key] = in_value;
		}
	   
		return tmp_previous;
	}

	this.hasItem = function(in_key)
	{
		return typeof(this.items[in_key]) != 'undefined';
	}

	this.clear = function()
	{
		for (var i in this.items) {
			delete this.items[i];
		}

		this.length = 0;
	}
	
	
}
